Taking high-precision Metrohm ion chromatography to an even higher level of autonomy, the Process IC can connect up to 20 sample streams and provide reliable multicomponent results for superior process control.

Matching systems to applications
Water purification is often a complex process; therefore, we have developed the product finder to help you select the best water purification system suited to your application needs.

Installation of reference electrode

Here you will learn all about the installation of your reference electrode.

FAQs

Chloride interferes with my determination. Can I use another electrolyte instead of KCl?

The electrolyte vessel can be filled with any electrolyte that is a good conductor. If chloride interferes with the determination, you can use KNO3, for example, instead of KCl. However, you should not change the electrolyte in the internal reference system. Using a different electrolyte here instead of c(KCl) = 3 mol/L changes the reference potential. This is also the case if you are using a different concentration of KCl.

Potassium interferes with my determination. Can I use another electrolyte instead of KCl?

The electrolyte vessel can be filled with any electrolyte that is a good conductor. If potassium interferes with the determination, you can use NaCl, for example, instead of KCl. However, you should not change the electrolyte in the internal reference system. Using a different electrolyte here instead of c(KCl) = 3 mol/L changes the reference potential. This is also the case if you are using a different concentration of KCl.

A different reference electrode is used in my application description. Can I use the Ag/AgCl reference electrode anyway?

A different reference electrode yields a different reference potential and therefore a different zero-point on the potential axis. Method parameters are always given relative to the reference potential. To be able to measure using the Ag/AgCl reference electrode, you just need to adjust all potentials by the potential difference between the reference electrode described and the Ag/AgCl reference electrode.

The table shows the potentials of some common reference electrodes measured against a standard hydrogen electrode.

Reference electrode

Potential compared to SHE
(standard hydrogen electrode at 25 °C)

Ag/AgCl, c(KCl) = 3 mol/L

+207 mV

Ag/AgCl, c(KCl) = 1 mol/L

+236 mV

Hg/Hg2Cl2, c(KCl) = sat.
(SCE – saturated calomel electrode)

+241 mV

Hg/Hg2Cl2, c(KCl) = 1 mol/L
(NCE – normal calomel electrode)

+280 mV

Ag/AgCl, c(KCl) = 0.1 mol/L

+291 mV

The figure shows the signal “shift” resulting from different reference potentials.

I would like to take a measurement in a nonaqueous solution. Which electrolyte can I use in my reference electrode?

As a temporary solution, you can replace the bridge electrolyte with a water-free electrolyte, e.g., c(LiCl) = 2 mol/L in ethanol.

We recommend a completely water-free reference electrode for permanent application. Both the reference system and the electrolyte vessel are filled with a water-free electrolyte. For this purpose, the internal reference system is also available dry with no electrolyte. The order number for this is 6.0728.010. The bridge electrolyte vessel 6.1245.010 is compatible with this.

c(tetrabutylammonium chloride) = 0.1 mol/L in acetonitrile, for example, is a suitable reference electrolyte. The electrolyte used for the application can be used as the bridge electrolyte. You must bear in mind that the electrode has a different reference potential with this reference electrolyte than with c(KCl) = 3 mol/L.

Caution! Reference systems with an LL Ag/AgCl system (6.0728.x30) are not suitable for use with acetonitrile.